12 Aquilae
Star in the constellation Aquila
From Wikipedia, the free encyclopedia
12 Aquilae (abbreviated 12 Aql) is a star in the equatorial constellation of Aquila. 12 Aquilae has the Bayer designation of i Aquilae and is most easily recognized in the sky being next to the brighter star λ (lambda) Aquilae.
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquila |
| Right ascension | 19h 01m 40.82887s[1] |
| Declination | â05° 44â² 20.7222â³[1] |
| Apparent magnitude (V) | 4.02[2] |
| Characteristics | |
| Spectral type | K1 III[3] |
| UâB color index | +1.04[2] |
| BâV color index | +1.104[4] |
| RâI color index | 0.54 |
| Astrometry | |
| Radial velocity (Rv) | â43.92±0.18[4] km/s |
| Proper motion (μ) | RA: â22.592 mas/yr[1] Dec.: â43.08 mas/yr[1] |
| Parallax (Ï) | 21.5669±0.2199 mas[1] |
| Distance | 151 ± 2 ly (46.4 ± 0.5 pc) |
| Absolute magnitude (MV) | 0.726[5] |
| Details | |
| Mass | 1.185±0.282[6] Mâ |
| Radius | 12.28±0.14[6] Râ |
| Luminosity | 58.2±3.1[7] Lâ |
| Surface gravity (log g) | 2.31±0.11[6] cgs |
| Temperature | 4,662±59[7] K |
| Metallicity [Fe/H] | â0.08±0.07[6] dex |
| Rotational velocity (v sin i) | 3.6[4] km/s |
| Age | 3.64±1.43[7] Gyr |
| Other designations | |
| i Aquilae, BDâ05°4840, HD 176678, HIP 93429, HR 7193, SAO 142931[8] | |
| Database references | |
| SIMBAD | data |
In Chinese, å¤©å¼ (TiÄn Bià n), meaning Market Officer, refers to an asterism consisting of 12 Aquilae, α Scuti, δ Scuti, ε Scuti, β Scuti, η Scuti, λ Aquilae, 15 Aquilae and 14 Aquilae.[9] Consequently, 12 Aquilae itself is known as 天å¼å (TiÄn Bià n liù, English: the Sixth Star of Market Officer.)
This star has an apparent visual magnitude of 4.02,[2] which is bright enough to be seen with the naked eye, although, according to the Bortle Dark-Sky Scale, it is a challenge to view from the inner city. Based upon an annual parallax shift of 21.57 mas,[1] the distance to this star is 151 light-years (46 parsecs) with a margin of error of one light-year. This is an evolved giant star of stellar class K1 III.[3] It has 12 times the radius of the Sun[6] and shines with 58 times the Sun's luminosity. This energy is being radiated from its outer atmosphere at an effective temperature of 4,662 K,[6] giving it the cool orange hue of a K-type star.[10]